1. A term used by the British to describe all Americans.
2. A term used by American Southerners to a. describe Union Forces during the American Civil War; b. Post Civil War reference to Americans from non-Southern States.
3. Slang for male masterbastion.
4. A term to describe pulling something very hard and fast (see number 3)

A word used by Brits, Aussies, and various others to refer to Americans. Connotation can range from affectionate to pejorative. Often associated with tired stereotypes of Americans being, of course, fat and stupid people who all drive Hummers and love George Bush (all 32% of us!) and can't locate the planet Earth on a map.

Ironically, within the States, the term is used by the people who best fit said stereotype as a pejorative term for educated, left-leaning urban Northerners.

Chav on bus: Oy, mate! D'yeh think 'at fatty what jus' got on is a yank, like?
University student next to him: It's probably hard for someone who's never left Essex to understand, but...oh, nevermind. I like those Burbory shoelaces in your trainers.

2. Term used by foreign nations, chiefly Britain and Australia to refer to Americans.

==> The term is thought to derive from Dutch settlers in the 1600's referring to the English colonials as 'Jan Kees' (John Cheese) which entered our language with the spelling 'Yankees,' as that is how it would sound in Dutch. 'Yanks' is simply a shortened form of it.